mem_detect.c
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/*
* Copyright IBM Corp. 2008, 2009
*
* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/ipl.h>
#include <asm/sclp.h>
#include <asm/setup.h>
#define ADDR2G (1ULL << 31)
static void find_memory_chunks(struct mem_chunk chunk[])
{
unsigned long long memsize, rnmax, rzm;
unsigned long addr = 0, size;
int i = 0, type;
rzm = sclp_get_rzm();
rnmax = sclp_get_rnmax();
memsize = rzm * rnmax;
if (!rzm)
rzm = 1ULL << 17;
if (sizeof(long) == 4) {
rzm = min(ADDR2G, rzm);
memsize = memsize ? min(ADDR2G, memsize) : ADDR2G;
}
do {
size = 0;
type = tprot(addr);
do {
size += rzm;
if (memsize && addr + size >= memsize)
break;
} while (type == tprot(addr + size));
if (type == CHUNK_READ_WRITE || type == CHUNK_READ_ONLY) {
chunk[i].addr = addr;
chunk[i].size = size;
chunk[i].type = type;
i++;
}
addr += size;
} while (addr < memsize && i < MEMORY_CHUNKS);
}
void detect_memory_layout(struct mem_chunk chunk[])
{
unsigned long flags, cr0;
memset(chunk, 0, MEMORY_CHUNKS * sizeof(struct mem_chunk));
/* Disable IRQs, DAT and low address protection so tprot does the
* right thing and we don't get scheduled away with low address
* protection disabled.
*/
flags = __arch_local_irq_stnsm(0xf8);
__ctl_store(cr0, 0, 0);
__ctl_clear_bit(0, 28);
find_memory_chunks(chunk);
__ctl_load(cr0, 0, 0);
arch_local_irq_restore(flags);
}
EXPORT_SYMBOL(detect_memory_layout);
/*
* Create memory hole with given address, size, and type
*/
void create_mem_hole(struct mem_chunk chunks[], unsigned long addr,
unsigned long size, int type)
{
unsigned long start, end, new_size;
int i;
for (i = 0; i < MEMORY_CHUNKS; i++) {
if (chunks[i].size == 0)
continue;
if (addr + size < chunks[i].addr)
continue;
if (addr >= chunks[i].addr + chunks[i].size)
continue;
start = max(addr, chunks[i].addr);
end = min(addr + size, chunks[i].addr + chunks[i].size);
new_size = end - start;
if (new_size == 0)
continue;
if (start == chunks[i].addr &&
end == chunks[i].addr + chunks[i].size) {
/* Remove chunk */
chunks[i].type = type;
} else if (start == chunks[i].addr) {
/* Make chunk smaller at start */
if (i >= MEMORY_CHUNKS - 1)
panic("Unable to create memory hole");
memmove(&chunks[i + 1], &chunks[i],
sizeof(struct mem_chunk) *
(MEMORY_CHUNKS - (i + 1)));
chunks[i + 1].addr = chunks[i].addr + new_size;
chunks[i + 1].size = chunks[i].size - new_size;
chunks[i].size = new_size;
chunks[i].type = type;
i += 1;
} else if (end == chunks[i].addr + chunks[i].size) {
/* Make chunk smaller at end */
if (i >= MEMORY_CHUNKS - 1)
panic("Unable to create memory hole");
memmove(&chunks[i + 1], &chunks[i],
sizeof(struct mem_chunk) *
(MEMORY_CHUNKS - (i + 1)));
chunks[i + 1].addr = start;
chunks[i + 1].size = new_size;
chunks[i + 1].type = type;
chunks[i].size -= new_size;
i += 1;
} else {
/* Create memory hole */
if (i >= MEMORY_CHUNKS - 2)
panic("Unable to create memory hole");
memmove(&chunks[i + 2], &chunks[i],
sizeof(struct mem_chunk) *
(MEMORY_CHUNKS - (i + 2)));
chunks[i + 1].addr = addr;
chunks[i + 1].size = size;
chunks[i + 1].type = type;
chunks[i + 2].addr = addr + size;
chunks[i + 2].size =
chunks[i].addr + chunks[i].size - (addr + size);
chunks[i + 2].type = chunks[i].type;
chunks[i].size = addr - chunks[i].addr;
i += 2;
}
}
}